What does IP rating mean on an enclosure?

IP stands for Ingress Protection. The two digits after it rate how well an enclosure keeps solids (first digit, 0-6) and water (second digit, 0-9) out of the interior. IP54 resists dust and splashing water; IP65 resists dust and low-pressure jets; IP66 resists dust and powerful jets. The rating is a test result, not a marketing claim.

What is the difference between IP54, IP65 and IP66?

The first digit is the same (6 = dust-tight) for all three. The difference is the water test: IP54 survives splashing from any direction, IP65 survives a 6.3 mm nozzle jet at 12.5 L/min, and IP66 survives a 12.5 mm nozzle jet at 100 L/min. For permanent outdoor use choose IP65 or IP66; IP54 is better suited to sheltered or indoor-dusty locations.

Is IP65 good enough for outdoor use?

IP65 is acceptable for outdoor enclosures that are under a canopy or not directly hit by driving rain and hose cleaning. If the cabinet will be hosed down, pressure-washed, or exposed to heavy storm rain, specify IP66. Neither IP65 nor IP66 means immersion-proof; that requires IP67 or IP68.

IP66 vs IP67: which do I need?

IP66 is protection against powerful water jets; IP67 is protection against temporary immersion (up to 1 m for 30 minutes). An outdoor telecom or solar cabinet usually needs IP66, not IP67. Specify IP67 only when the enclosure can be temporarily submerged, such as in a flood-prone pit. IP67 enclosures also need pressure-equalisation vents to avoid sucking water in as they cool.

Does an IP rating mean the enclosure is waterproof?

No. IP ratings cover ingress of solids and water under defined tests; they do not guarantee the gasket survives years of UV, nor that cable glands or unused knockouts are sealed. Real-world protection depends on the gasket material, the compression when the door closes, and how the conduits and glands are terminated. We rate the enclosure to IP66 and supply matched glands so the whole assembly holds the rating.

How do I choose an IP rating for my enclosure?

Start from the environment: indoor dusty = IP54; outdoor sheltered = IP65; outdoor exposed or washdown = IP66; temporary immersion = IP67. Then confirm the rating applies to the full assembly including glands and windows. Use the IP rating selector tool to map your environment to a rating, and put the rating on the drawing so the gasket and test plan match.

IP Rating Guide for Outdoor Electrical Enclosures

IP ratings look like a code until you read the two digits: the first is solids, the second is water. For outdoor enclosures the choice is usually IP65 or IP66 — and the rating only holds if the gasket, window and cable glands are sealed to the same level.

First digit = solids

0 to 6. A 6 means dust-tight — no ingress of harmful dust over the test period. Below 5, some dust gets in.

Second digit = water

0 to 9. The number is the test severity, not a fraction. IP66 is a strong jet; it is not the same as immersion-proof IP67.

Rate the whole box

The rating only holds if glands, windows and unused knockouts are sealed to the same level. A 12K cab with a bare hole is not IP66.

Reference

IP54 vs IP65 vs IP66, in plain terms

The first digit is 6 (dust-tight) in all three. The difference is the water test — and that is what decides outdoor suitability.

Rating	Solids	Water test	Typical use
IP54	Dust-tight (limited)	Splashing from any direction	Indoor, light dust; sheltered electronics
IP65	Dust-tight	Low-pressure jet, 12.5 L/min	Outdoor under canopy; solar/comms enclosures
IP66	Dust-tight	Powerful jet, 100 L/min	Outdoor exposed; washdown; roadside cabinets
IP67	Dust-tight	Temporary immersion 1 m / 30 min	Flood-prone pits; submersible sensor boxes

Tests follow IEC 60529. The rating is for the enclosure as tested; field protection depends on gaskets, glands and assembly.

Choosing

Map the environment to a rating

Most enclosure specification errors come from picking a rating from a rival's datasheet instead of from the site. Ask three questions: is it indoor or outdoor? Is it under cover? Will anyone hose or pressure-wash it? The answers usually land on IP54, IP65 or IP66 — and only rarely on IP67.

Use the IP rating selector

Gasket

The rating lives in the seal

An IP66 number on a drawing means nothing if the door gasket is a thin strip that relaxes after a summer of UV. We use continuous PU or silicone gaskets with controlled compression, and we supply cable glands and vents rated to the same level so the assembly — not just the shell — holds the rating.

Polyurethane gasket: good all-round, resists oil
Silicone gasket: best UV and temperature range
Pressure-equalisation vent: stops vacuum sucking water in
Matched cable glands: the usual weak point

FAQ

IP rating questions

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Send the environment, get the rating confirmed

Tell us where the enclosure lives and we will specify the IP rating, the gasket and the glands as one package — and test the assembly to the number on the drawing.

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